Japan's key Nikkei index closed above the 40,000 mark for the first time on Monday, following gains on Wall Street.

The benchmark Nikkei 225 index added 0.5 percent, or 198.41 points, to end at 40,109.23, but the broader Topix index slipped 0.1 percent, or 3.14 points, to 2,706.28.

The dollar stood at 150.28 yen, compared with 150.11 yen seen Friday in New York.

"The US high-tech sector including chips rallied on the back of falls in US long-term yields, which prompted purchases" of high-tech equities in the Tokyo market, IwaiCosmo Securities said.

Tokyo and other major global shares have steadily gained since last year, and analysts predict the Nikkei should gain even further, lifted by rallying Wall Street, robust corporate earnings and strong hopes for AI technologies.

On February 22, the Nikkei finally broke through a record high set just before an asset bubble in Japan catastrophically burst in the early 1990s.

After the Nikkei climbed above the 40,000 mark during Monday's trade, "profit-taking sales grew and capped the upward movement", Daiwa Securities said.

Among major shares, high-tech investor SoftBank Group added 0.3 percent to 8,934 yen.

Semiconductor shares rallied, adding to recent strong gains.

Tokyo Electron roared 2.4 percent to 39,290 yen and Advantest surged 3.7 percent to 7,380 yen.

Toyota dropped 0.5 percent to 3,662 yen. Uniqlo operator Fast Retailing slipped 0.5 percent to 44,170 yen.

Shipping firm Kawasaki Kisen dived 6.7 percent to 7,232 yen on a weak Chinese indicator for container freight.